Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1270624140 -3600
# Node ID 7794f61c61f3b0c90e367a87b287850b31645742
# Parent adce8bc43fcccf8730b1da962be60c457c51fa1b
x86, cpu hotplug: Synchronise vcpu state earlier during cpu offline.

Needs to happen before non-idle VCPU is fully descheduled after CPU is
removed from cpu_online_map. Else sync_vcpu_execstate() doesn't work
properly.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
---
xen/arch/x86/domain.c | 3 ++-
xen/arch/x86/smpboot.c | 17 ++++++++++-------
2 files changed, 12 insertions(+), 8 deletions(-)

diff -r adce8bc43fcc -r 7794f61c61f3 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Tue Apr 06 07:16:47 2010 +0100
+++ b/xen/arch/x86/domain.c Wed Apr 07 08:09:00 2010 +0100
@@ -1442,7 +1442,8 @@ void context_switch(struct vcpu *prev, s

set_current(next);

- if ( (per_cpu(curr_vcpu, cpu) == next) || is_idle_vcpu(next) )
+ if ( (per_cpu(curr_vcpu, cpu) == next) ||
+ (is_idle_vcpu(next) && cpu_online(cpu)) )
{
local_irq_enable();
}
diff -r adce8bc43fcc -r 7794f61c61f3 xen/arch/x86/smpboot.c
--- a/xen/arch/x86/smpboot.c Tue Apr 06 07:16:47 2010 +0100
+++ b/xen/arch/x86/smpboot.c Wed Apr 07 08:09:00 2010 +0100
@@ -997,17 +997,13 @@ static int __devinit do_boot_cpu(int api
return boot_error;
}

-static void idle_task_exit(void)
-{
- /* Give up lazy state borrowed by this idle vcpu */
- __sync_lazy_execstate();
-}
-
void cpu_exit_clear(void)
{
int cpu = raw_smp_processor_id();

- idle_task_exit();
+ /* Previous non-idle state should be synchronised already. */
+ if (__sync_lazy_execstate())
+ BUG();

cpucount --;
cpu_uninit();
@@ -1301,6 +1297,13 @@ int __cpu_disable(void)
cpu_mcheck_disable();

remove_siblinginfo(cpu);
+
+ /*
+ * If we are running the idle vcpu, sync last non-idle vcpu's state
+ * before changing cpu_online_map. If we are running non-idle vcpu,
+ * we will synchronously sync the state in context_switch() later.
+ */
+ __sync_lazy_execstate();

/* It's now safe to remove this processor from the online map */
cpu_clear(cpu, cpu_online_map);

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